Hadfield demonstrated why there's no crying in space last week, in an instructional video from the space station. He squirted water from a bottle into his eye, and then showed how the liquid just kept piling up on his face.

"If you keep crying, you just end up with a bigger and bigger ball of water in your eye," he said, "until eventually it crosses across your nose and gets into your other eye, or evaporates, or maybe spreads over your cheek — or you grab a towel and dry it off. So, yes, I've gotten things in my eye. Your eyes will definitely cry in space. But the big difference is, tears don't fall."

"Tears Don't Fall" ... that sounds like a great title for Hadfield's next orbital ballad.